SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c9c8b253b3a6fa8247550a7d6959291bda428a43508e71b459c5c9b85aa69ef' 
  AND token = 'mGDbd9HHBAnXGzeAsVz1pga8YrmwgGYQppfZVJ103as=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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