SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '81c4c413873faf452211ad9a88054248668d273958ecdd2f529c2f222ac23ac2' 
  AND token = 'Zg118HvrLpX/+5Z5dVth22ibESLvG+7MPGHVF1I3Ywk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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