SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '762580e4cd9483868739262b38fa23c53885d2ca9cbe9b631bffe7ce8dad77f5' 
  AND token = 'zFQsWG8PPqAfl+whppgJJqrOOxbxlkSP4eWOpcM8PVE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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