SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f228c6757fba82c01d01fb5a64681dfb417c0da314547525331924370ba7c9af' 
  AND token = 'feOfMsdFndnKpiBeHx30ZOS6tXFv20rpRMMdnf02ZQQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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