SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0b689eefdd4fa2bd339b5b6f626915ced921c51155999460d206f0c20fe38a1' 
  AND token = '4Cv79Z5h+fUC6XMMrjEbAjaly3x4pn5PDuMzuWU+g7E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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