SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '231a3f305d1effe632b00c27f39109da15b2312ac21b1d354e8046ed89a276bf' 
  AND token = 'uvzVZ/YRtUSwSrltffNigPcGAG9Ftt1LQQA+TSI22bI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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