SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '9e7e0a398834f2be0a6124dfa0b4479fbe43310a0b2d9f241cfe4018117433ba' 
  AND token = 'loYY3pGpyyJNWYIlVblaT6gVLqmltLqKmvflLZMsL/k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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