SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '26d8d0648b18416135e34019fb9258a28ab014c0097383d534c9219bc4880b29' 
  AND token = '1FCJf54oUF83KHsfqy2vIerCwNe79v/sulpmnvzs8aY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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