SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '488c7e750030ed5074655ce960956edfea27836b365debbc5349ef6a36b1b19f' 
  AND token = 'KF297Sazt672A5Uit8gv+sA3Ui3EHEWa/gZyvNxhtyg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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