SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '234311f5734eb15b90df1510d74adfb7793a80a2bc9480b0d9ac5c687e34dc25' 
  AND token = 'dzgWuy809laWzfaiGVkWgnRj2jPovmz0ABVLKUnLZ6w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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