SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1d4cd3374e4a0e29f81f1b023e395e30f8e55d13b359b7803049b9959bd4169' 
  AND token = 'GAj/rPQKQoMyMM4nK7iBeWvlkSRf6WfJQxJIxMdnmKM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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