SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b85c2644a609f4244f91b7890c15c75110d205217612f51f888863ded612b9f4' 
  AND token = 'dlVPHEhGFSIo6H2g71jPGfmmWwaWUJRkZiY0KBjE8Ls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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