SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e9f9d5b7d019c2892dbc5858a0c497f4269a6b436c8acb52ffad0f9ab26ffebf' 
  AND token = 'MiDauupoOBLaoT0qKQy3inaT1RkN3S8AsVbzZ4WiJMM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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