SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5560f59f64119ab1776469c1035924a0defc6c53785700767c304a94a3b5248' 
  AND token = 'QS4f1JaOghGzJPtbqlOHVrhZ6OvAeWO5+EY/l1HiPzM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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