SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'a8cd4722813fb26f0fac9a54dccc9788c08f8d49c968d751f5f46b0c327f7307' 
  AND token = 'nhjRcp3hRdukc5u1VIQzsXtv3xLHaWCSyQVwmQytF14=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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