SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a461477bd1df8fd761bc229e24899f134b382312128ba29e7310c69d6f51a1b' 
  AND token = 'yFhhtf1RpX+5zj9Fo73/asvGDdCmhUcYy8JQZJCp3gQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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