SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e78ff1102c81a2d70c4b8fc61b305fe19d826ec3698bc6004036b4a162389759' 
  AND token = 'QrNLoqoOsqgh2GqLtG+9g3y632mprhfv06anNsB/8Mw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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