SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '638d92bdc452d1f1c75aff1fb3ed643ee42cb0a2fcceacec18a11d998959b4e1' 
  AND token = 'heyd9NJJrmEgPZe9E+rIEkjetrN3H0ywg1KgasdHGcQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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