Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'add74821fe1bcb8d52663bcd8eb059c8974b998752a3bc1d8ee39e4ad646f119' 
  AND token = 'SKPp1ZqSARIpfHMlXSkjEARXrIWdZ3oUnOVpF1gqm+4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}