SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '749e9f0106bbc61cdab085efffc444e840a2e63d79541f26f93121d05e6ff633' 
  AND token = 'qeZoKcnSGBCw//RJ0hw9TmJfTyqFqkwX5u/Wx98bS0I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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