SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff7e33acbf82272a8a4714c118ee58d9ceff5616070b34c0857686684dfaacba' 
  AND token = '8dV4DCd7preSXUoTOKsAsaDafBDVEVfJrzWNFJUe1KM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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