SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dde87588a672f04e4776bc684452501b61bdbc760e45c814a066e29623bf0210' 
  AND token = '1GN468OZd9DZbwtP3V5MJgfWbM9jUIV3ziJ5TKkVxZ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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