SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90e2307ddeb458f1dfd1ffed89c10394f6d9f11293aeffd0b7b713579f76382d' 
  AND token = 'Gpja7EwXxJcGpI9wjdqo/oxGmMBRlkEbTsineHnVd6k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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