SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1cc2a27ed4897cd1b17445d196b0b789f166e3f01d28247c7cbc329e2195cf98' 
  AND token = '4le30OA2hGUBHs8vkVLsX/fd3xk5mVhz+Ui29FIS9Zg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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