SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58ef879cbdc52847b05f6c74bfcc83aa3d7c7de4cfcf48d62898b6152f3fda52' 
  AND token = 'tbcUxsSpxGLXa9uq/tiQpIjzALVBKeMTHgpelNCoRdo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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