SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de654fb76de662fe614b6aaac28104a4016ba524156f95921da75613d46d31f1' 
  AND token = 'xBztfTnQ/4Vtr3IbKyyfLclSpLX4HGPQmK42cN+67gM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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