SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19d726a8fbae1ba1cac26cbdc1f67bae9a98825d3f77b7d01e973a27b7e708f7' 
  AND token = 'HfFz2nwQzCm5T2KYbFVsLjRolxBuE+wUL8/gStrHw7E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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