SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8cc1cb784a10a536b31f7b1b8d6fae00947363a77f4f9d0556185e432f51a179' 
  AND token = 'xiyVDgewcWvNvgY29s+F4UrOjx8eLpqZjjGLCV72Euk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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