SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48da7ad15bb207523adaf565e42d9a1307e2875f3f0c8c8032721096ef5c6d3c' 
  AND token = 'B5CH1DoYWNKfHrI2fAX7tYBxT5Yj+T1NJRzc0CXegVk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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