SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '016e8e8e0c80b383bd5bed8982fff1c942bd4603ff908b16f5247b5c751fd50e' 
  AND token = 'Nu1J7xcjnDmmKNjx6wYCoEDGIgQ1ISj85PD3JE5c2O4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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