SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af7fa8559c2948cd8dcbe9c9048c0a0f76d74642bb7e967b7eaeffe03fdf9541' 
  AND token = 'LDZ3GPCADLcRmXRCjn/3a8YHJrI7qGqSp7D8VvvYX8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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