SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a04a1d1b5df2f8bfbe5696cf1bdeae4331c38adc0fa52d3d36bec0c87eb6066' 
  AND token = 'AJU+KlaA34D4s8qgOL+Nn/BVAafSZ6UL7MTWOUjO8DI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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