SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ff284c5dad69fd73c1e0431b3aed178b200fe245d1c27f85fd4bf2ccd406700' 
  AND token = '0H2tuRuhs4sObwf41R3aE79iZxb7wFrTQnpdkZQoT88=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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