SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fa125e6f620e8137c3c18e26444561aa9b6b53827291de668bbd03eed785a46' 
  AND token = 'T/X4bQN4PTkjVHfNIaDgmdYKPNIfTB2qnWFPRSXIVOk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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