SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c04d51caeb5f7ccf901cd664cd265586ef77b29a7f5d4bf02bb3647585f68f27' 
  AND token = '+taSx1lS3cbR4ePY4uDRXADPqk7uzXxREsn7WsdSqt8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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