SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2610abda98277511753c697ee716b70cc1bc67efa9070b31a5808426d3570a6' 
  AND token = 'hiVZDcVegx3fcM0mo7mL6kXGIqXWSOy74uONWYVjiF0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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