SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1478402e24d075522beea47b9b24e51c561632fd57e567206b9f6689aeff5ec9' 
  AND token = 'PSgJ6heAoiCo5uCtILpg6FR7XiGZ9PZVy6MI2YWsMLA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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