SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fe0db6164668dcf1cfad78c21ac9bf73c1996d3f61b4ecd32aaf110e0dee84c' 
  AND token = 'vK/6Vgr/AaWW7MMLH7zXgEqWRdBkBxBnb6CB34wmMNE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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