SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58faa1b03588539c1eebe278c8dcdbb8eaa3a6aea41161c547c3f4e258625f75' 
  AND token = 'gAmqLr/luvQ1FOnbz5RVkMRXr8qna0WUFx5/uTaEZFk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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