SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fa4990470d95d86e618b93d7a8dd47a7552f82147d86b7679de3d1e94153d49' 
  AND token = '6XiBEnN7rvKB1XhEgGdF5UmDVvFFDmCzcZKvqV5PDcI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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