SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71c40e9bc4694a7a3187dcfd6f2efff55ab40225807936936ad727d518902be6' 
  AND token = 'jDnS3EdGjJJbGAdC9oRHJm5XBmwvn6HdZfG9gVpvrYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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