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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9d95d9c5605a8b993fe7f387781b9f1f4e138111d2e319bf8c04cb69ed1818e' 
  AND token = 'rS2Ef3vKc0RAbItERzECMmBnA+ZfR5+FCCIAsY05dUQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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