SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '73ebf517d9639f73afb77a8bb9f372bfaf25ff4019c7f5bc6ddf008ad3ff0bd4' 
  AND token = 'p6aP+/HQlBaGurKTblDxxzA3MpJRLpCYJ4hndW7X5wc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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