SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c53c4a5b1a4d7aee6f12ee7c81177baa9f26da6d6858311b87c809511e901660' 
  AND token = 'NoCpFBgiwZkwkxVOJ0UWW7/mIAMfjfvQ7YNvbG55nxs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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