SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a028c16e498158d3c127d0d237c6a9ad5662af919dd45c7100edd2eaa2dbdd3f' 
  AND token = '/f3qJTmoBonj3WuiLfNQKRYJuaxdayiKfzk/9yRnBAc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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