SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '705fe54f855e5bfc2101aa1b54dbc3f62fc74e964f280ffe881fe62bf51821d1' 
  AND token = '5UaOgfomt/SEk985bGlQsMccPIdPUTmWBzaKvZYhgMs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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