SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd999fcf95d51f8f68870fc858c983371e7d5bd916cc773b6fdeb7f3bc6d9e89f' 
  AND token = 'zUiIEbfXYSf7Q+tKF2QgHrVZFoTMVxfQcMNmZzTWZyk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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