SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cdc74a74d603b3de87b24e1d02ecc5ca849e218bdca2213bbf907f6c5b311d25' 
  AND token = 'VjIlaD7ED8ZFP+DFZBc2VF6AUdWfZlD87o9gUMhf93U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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