SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93ee4fe757019811fb9a8cb27ac26453d6fc8702ab9e56311bd5b48a10c93328' 
  AND token = 'qqplMw1qjWKinRg56xuN9CXQQGcAbJAtXaC7TV/YPN8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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