SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70540b6a5815fc2d4f2b35005321e4c3f30831131b78c7c27b4ec4797985fe4e' 
  AND token = '5sSID8Q+ViaiRDKlGheEY2ZtBUiyDiXgBwrY/TKj9eM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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