SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '574296a69378faf4b8eff4f919c35b4b5f7c5b0fd96e44512b357ba5bc6381fd' 
  AND token = '8XjfuACbZhBuROEYKzzlEh6upoiqoRtq/mcg9SR28ls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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