SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7eb4323e99b8720b7777b29f56bbff267f2b1d80b788ba773ee592613b57f56' 
  AND token = 'cnYyhJuT41GBjhd4prkFgs7rqJlNS/uBmlhHVDu/GFI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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