SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a823338ae797819fe4b4f591840fb37fb6d11feb12a35d377f8792ff3d0d2245' 
  AND token = 'L8Ha+e2LhN+w4EJfzHLFSFdNojqqDc2eSXn+EG3oAGY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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