SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c942364e358b76c0b699a6ce8d4c22dd933b43b11094d0bf3f75b794f75d8530' 
  AND token = 'mMtPoIhiaMCPVZQoQEB1Kzh1agO109Ow9SLqNRfwKLw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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