SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae064bd91205fbd27154ba6942c4df4b87bf628346bb7c6557d54f02a8d9ba00' 
  AND token = 'AvRyiWafApnrJHI20y0UlWmISiz3iaHreCT41AH15Qg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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