SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89a83f703665b505b953c32feec16e241616d1936fdb762acaebf34f6647384e' 
  AND token = 'p1nylRrlnWNzPxWpq6Ui6sMweY7eyYbF61kVEO6Fv4s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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