SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8189c40ffb953722fb987efa7aa2228da58b6d7ec8a8d5b423667865946a1128' 
  AND token = 'kdMa70uFysNORsou3h8IFWUa/PnAhBLqsFbEBRfaxGM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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