SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c3a80693ef5650ae6e197fda6bded638833857dc49a4b5e7d4b9bfb723e7969' 
  AND token = 'ZXyQKyYmhMzlOpwWRvv2qyZO5E+X8l8tkqqeL9ezu7g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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