SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd324f5e16493157e1daa73692d62ec1f78cd4599374d46f032012236fadd96f6' 
  AND token = 'hJBXl/E98Esh0ASYgZjTlwA+OYfXdF4565y8KAHemSc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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