SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4af983e8f46f5a20ecf491591574f82218d5fe0d888f1949c8eb788767d677e0' 
  AND token = 'VStRNNQBbpiSMIEBOCP0JU5NOgp2uQIYTO9v6/VunsI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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