SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e3a5803ef507f85af4ad9c92a4f30822823f477b613e4c0bb74bdc99972f2a8' 
  AND token = 'OuG+jPN4ylSWCjNqlygR3h3oLQ6Y5Uuh5hF/ZKePRSk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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