SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de66d37bcbea111972d5858ee4b8119ea58c181e2d03a20e27cf719bcd019c18' 
  AND token = 'Wsmvt88J7xYXuswKMwpND3tklvlnLah/qim2s2sh5bg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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