SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ce4380f97ec5420e1288080d58e60170e7850ca4f48917595fc7391f6af89e4' 
  AND token = 'up6ESX1uxxXTqgKBfrShgS5uwbMdQAN1AXmFS/TQEp4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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