SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cbcf668b071478a2975e6e2b821bbe2a70d0dff485ea744132b03743f62b5679' 
  AND token = 'yfFItIf3pkxD11tLmDKETNe+xNHAV1FNfAULivUk2tI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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