SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ac03a6e6a3fc9525dac8ebd85ec3b633d34c8790c336f18fe91d030cef4e670' 
  AND token = '2DQ0lCjvjSNCycYfovXWoO+uaGQNBJ0kzm9EvQjgKd0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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