SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ebc46f65e473b98641a4e20e0910f03bc66a4ef38579f195c6cb4ab6491449e' 
  AND token = 'RHBvwFpUXwBha/JpPUxOj6BEEM+zu9W5Qt+uBZnYpPw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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