SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82585f3d048e0a401d23823d315ca94e5f17f187319f9fc434b2d8128a6769e5' 
  AND token = '4nqyWTlQ+zAhDNUzmM2iMaxACYOEsHqPFGxQW/hdlEw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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