SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab83d498b9ed6571e5120499a18b357f47f00c41d3fb55f4edffda64efac012b' 
  AND token = 'liq2k5I4KwFnUzBZqKRaltcGDTfMjDO/YM0Kt/Rqchg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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