SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c46d91df0cdeb17474a5f43ccdae7cba1cb0864905e4e218360d02f181c63970' 
  AND token = 'eOsXCoq5MMI2KYxuEvkFKOLXAvEKEC9qUb8LKd79uvA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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