SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff8ed2d3dbae984883c8e6b9802392d979ae5f0425a1512fc4c391e67f650f17' 
  AND token = 'Cd0t3/7fMMJD0T6rEtvPxfQ9zrGg4y5wm11+Zznaspc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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