SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'af550968fef017caf8d421a8bfa0685f10b6316139614497ab7974ed07bc681c' 
  AND token = 'YXyBPpD9E2IDHEvpM6/Rwnyyy77nNTEMQkdDFBM7D2U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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