SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b13828ee431436882d7411343f05918e31c82786a5c71a59acc5f97f19e9c22' 
  AND token = 'mk2AZQFQ+CPoNg1tEEZGpqzN2tXgwvV9UZOjJcEN0qo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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