SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '868468b8a289887ddbb8a0b3101ec37f712bf9c0f1e120cd68f73dc6b3344625' 
  AND token = 'Hw+tRVeK/VAB5i+dk7+qZjcvX2JiaStYyBhfH8iDffw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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