SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '816b465902222f619ede48dc8f54005214c19e35fb9a490210f9cfe4a4fbf6b5' 
  AND token = 'C/7oV2ipjcP3swHBKsAD3rknIPZhQ5+Pze7ULTdE9aU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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