SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '63349e46d9b0cce16679f1161f86df053107d31ede4d09d48b8305eb2e15522a' 
  AND token = 'Rt8beUt+QQCnbZ8Ba6SZD/MNK5ehPnqqtCqQndJBwrM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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