SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49fe7f707143682e2f0aa59bd412398cb2fc5997d9d19371a21bc9f5853be018' 
  AND token = 'Xu2WJ4tnedKhV36zHwKCpnFnM3HP0FChAiyK2UrBcr0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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