SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dff1f971e6895668c4cb0fca2fc670b16539c9478fa79e0070658d13f3aa6a48' 
  AND token = 'fCyTSxuovBRQuhpuBoJv/bo0lFabqfW3O/XwOM3dgi4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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