SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30910d76da4c762b681fd40f04be044ebe6135a8b6b52f946c6a3f8ca0a9b3c7' 
  AND token = 'K1ZQ/M9jlfkVacIvB5YulCcN/+NAwmz5hGLp6XSquu8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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