SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '752d496abdc2870a7d03ca5628602c228581296264dd399a586965bd546b5207' 
  AND token = '8kP8pZHaKIlEQC+jPd9we35sxI4yV0P1YlTfcM4NhTM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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