SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb17802c5f93b06bcc7957bdcaf53bfa8f1c552cdd6684a8496cc0e12624472c' 
  AND token = '+2Iz0v/sT0JFe4yXhYua0mvRuGdswJ9ZkE0HRPYNCwM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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