SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f0312f15f848d6b084f8cccd7910709b356ed60f424f07214393804c0d528c8' 
  AND token = 'K1biEaoqzgbxDJkpPazB5SqzszCLwY1CLqiYacMPIFs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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