SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e6a54a252115c51672a19172abd1706a64eccbeb14c98c5f044538a2f891ea4' 
  AND token = 'FUkm/3f79tP3j6ddvbqd6d8A0FTg0buOdiPZ/yUa0EA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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