SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f23642a6f99a8458fa9dc4b94d6bc8a5020a12b5233c51973e1b126cebe5d16' 
  AND token = 'NLRZptRznq5lJVKFGkDDqC8TFPUin1/YVBDIFCbWZRU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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