SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb19a6ce5cf2afd6cb5cd212a1a40440115d57537e6ec791d9853fbdc79b40f4' 
  AND token = 'wkuLTEHHUVpj7M/xQsuJxeFRFug5tGeZAThgh5XJDDM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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