SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9b5894b4583b9b7c0c98fd9952e8577595c16540dde33ff991e08310508ccf3' 
  AND token = '3D4DVqKi7zRWBFYXJiU3XixjR/hVIZbSIEEMD5LjZeE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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