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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b1478244d1afe37fe733ff80b1420b4a411ca91837ebbdc6f6f6c9715b9776d' 
  AND token = '7mPLSxQAnnUs/mWpbBvFSMg8kxOvNIp4RT430TjBMEI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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