SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '323e105d0ea4aa1bf98eb3fa9367f32f7064d273ec73a998302648c1e1f8cafb' 
  AND token = 'KMYn93jJkAhfOCY4sYiBpdJPCsAVn+l9XqrNRN6QxQw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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