SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'baa3e546f96886e9da05229f54ec94f926c5de3177ac1385dd9dbade71ccc3ac' 
  AND token = '2HsrlVjSYXhQCqDFUZwAg+pxzb0XrUU6E4Nin0V/+WM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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