SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '1b21da364e4d84dfe3f352336d1c473e284bf99c6228e70a312c67fbbe9e77d5' 
  AND token = 'tfige+37WIrpzRxWnDCG/CNvD5c+StR0Xyu0yII2wWM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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