SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '116acad9691badb4425b6a42ce47ed07bb076e4c4384d607da6703ced985e11a' 
  AND token = '6mZQCz56KFmVX9GwYLcTl6T8oyKQONZxyfhAK1jcOnE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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