SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a337965ec7165601982b10980b1b3e26cdd06d95153c79be1e85d2dd29a07141' 
  AND token = 'gIWBRZkFmjONjuenS9FQKcEzk+9oFxMkHjQ9QEkX8fQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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