SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6b38094a7e938f57bbb1ad5c44789d36e014198f8518e772b66308c1f01b6b00' 
  AND token = 'Mo7StiwVkhuBjBs5FMNxg3+qRS9zWHOTE9WuNFpl35g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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