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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b4a8f19d5aa41b03cf0f81dc909a78f1bb695f7c6e8d9dbdd5d0e93677cb821' 
  AND token = 'ZIc2zkn+5ivi8py8hxp+ylACA08Dav7LKGkbYYHx0PQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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