SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '21b8d48b558c343aa355e178f2ab806f68664c6ae9241487edeee66466d0cf90' 
  AND token = 'Wj5vvWzdXwrpqOPSwhJsZrSVYpgIzN5S7Fv6eGX81aQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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