SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '69921e18d14b88021780b9280aaba0d32e7ba44c575b2e5ef124505153ea726d' 
  AND token = 'hxujUubi5SlFLGMpKIWy4FbTDOTBuUEw+7EwiuoK+B4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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