SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30d3743a9680deadeb45291d02db73dcb2fc039aac91a0ceb9491d0642db32ce' 
  AND token = 'sXEkGRbh6v628GltDBqvtEYEWDf+C8FCRpc5T/7rRqM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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