SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c090777951c6773acaceaeac0dc9220544611a03a39ffa999f709afe3cc6e6d9' 
  AND token = 'HvHWU31B+hxixwHLspgnSbsky70qWguPpRTF44wFj/U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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