SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7993e9a939346c58769350c4a0396fe1adaa4a26f5b3b10c7ef4288196e67dc' 
  AND token = '3hWjRFNQyhZQxXCV+TvjmP8NwFcbBZfM7VpMFmOi//M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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