SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '394ab6344194ab9a763703df1ddb2335bc29487bdcf8d2a1e5f5f763d2de9e6e' 
  AND token = 'YTBg3knIeQYXjIhOZHHwOY3PeKSeYz7960OJBY/hStY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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