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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b340211aa52d13387c951b1f123218cc973aba3cb60493f856e3e3da5207edfc' 
  AND token = '8cGSaTHw1YUaLMoC7O17ST5qUBaeEOJlPNsURy4Juo0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}