SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36f8c930f6cc3520f7ea20db96fb83031ddf1edd5d4c4d39802bda97f9521867' 
  AND token = 'wlKOdtqsy7AGjofG11NYftHsPirquhYie8nkRI6vXCc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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