SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1cb2a3350491f9d816727cf36ea533cd61782bea695230f1af3b2ac5af8458c' 
  AND token = 'Fs33TlQTED/5RgKzlbns6ztKvst2JyvtZOJtwDgqS4U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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