SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff38c4a355b618f5d3157699a044d835958971831074af7f786db326c4fc8989' 
  AND token = 'yoUh9jubLD2ljeX3PAnqbitTc5Ron/KmyOw/F3gSy44=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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