SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6d6f422c33f2d4f247ed2ecd910f8068e81f2d0b284306235e00d725fada3a41' 
  AND token = 'VhJoe1K6aKOEbwadt0FTicHjeWlWGfml+i0zcaMRVbM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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