SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6af3972d12149042f134155d4f4de7ab5a7d02766e66b770362a59a2f6bc4d2f' 
  AND token = 'F1SoJplvBZkFOG1HWBzCHUgd6GIFSuEitfrM8taOqck=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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