SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b87eaae339aaaffe09fe95e7ac3c87b39f159bda165548160be0449e8004f9aa' 
  AND token = 'XuR0kITLXVeKiJ5E3qMc0ZM7uUiT9+rwddOQLtrJFwQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00065

JSON explain

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