SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83a5402c16f005cd32a99d8cba218952b0329f73e5073000e05fe71852a520ec' 
  AND token = 'nBRo9cZUIeDlkonaRiOxCdQuOIYErzC/OhiaGXLg/iA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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