SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5ca44645bf6999a3d543d19d053fe15bee8054af2f49a4386d2c77536aa0720' 
  AND token = 'huEWarQNyPrpZSiQoZd0lB9jU8wnKThKfHybVWl2e80=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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