SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6621924fd31d354c86ab7b35625b8b708c6c339daacbfd0f622fb4d847e7c135' 
  AND token = '+ac+DBi3eQNOkuFEqvmsrOaFZG1OHGVh6iqDu+COVjw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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