SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86bd32414d32bc1dc9667671c6d8c03e0ad713ce992b0993ba081e85bd972f80' 
  AND token = '29mcN1gTQFtdjWMNFfTlFOrjoemV3OOyj/LiGMWB9zM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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