SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7187eee87acd453d9a1d9501b63727bbb58f913efb525692f5e13fa81b95018' 
  AND token = 'lnSpQVlDcgiMw0pm+8qAVJGulMX/qSFKJzJ/rIi15sI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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