SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f78887a7222f076c1d08d53a44d2e418226fa71b1afe428e3cf91fdde69694f' 
  AND token = 'IB3EYzjElxSxw6Sit/WYXW9jViEmG4apMnm0d/1ZOcE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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