SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a16d1a05ea79bfdd924e8c9866d2606a94ee8b8b5f389702cce07b8cc907fc61' 
  AND token = 'QcXW/e1OqwzhN1myXLLkER2ckCJjnwk3TIikWrOSrRA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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