SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb5e9a4b1f7c1855acb1f2395f768d3dc834dbb092d44017487ce4054ec48ef6' 
  AND token = 'srYwAQHD0mp7cFy7GQGG/2JeDjUiEAgfZoTRnvX9vGY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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