SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '935078f0f4f01f300b6d39cd2a031fa1393f4693a321af194520f8ddb3a7cafa' 
  AND token = 'CQuorZbAXVWRDlDwMcCplae81ZjhAK6+YBxuZUsERKA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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