SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c028c500ad919f4ba674cf5d3c4c423f0cb4bf0f24562b7ffcce707ad4eaae1' 
  AND token = '7KZN7TD7rYSTzOspwyBLv1+pU3bpxcAIOw6WOtqhojc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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