SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '53e46540349321a16d23c3c0019c9c93b27e2ccae713aeb5442ecc10be6a1ac7' 
  AND token = '4WIaT4gsBQ/bt60+ffvEZNtAxM76QQMn761oH0VyXTo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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