SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6338f10158526fe30cebfda1efbf128f074bd15ebb61de0fb9f53cb72f1e43cb' 
  AND token = 'PikIS71XxuDp2vln270Q2TBkcha+9AjT/VRB/S6D7kQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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