SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7bc0b0457d1507fe78f6845ff56fd49fe3d69c5cc8045860393020c1be84fd2b' 
  AND token = 'b1NkhVkF51o1w1V9Tu5n+i/tUb7TkxuM1GTgj/4UDjs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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