SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a932a22c887b515cd6de4982b1ad0ab6ce143618ca5ae804342088d92a1a7e2' 
  AND token = 'pDILqvO/gtrfBAZ0nLNKQ+wzq5JWvYuZ7YoYG0zYdjc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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