SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d0024d845fc8e957d0d8c4f674bc50f5ca54ae7bee918d0aba077845daac7dd' 
  AND token = 'Nfb9aX7GGf+nUoDdd+FZf29Ovi2eSthRPeZLqgn0ZI0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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