SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '31491f3f43142cb4d8277a925de524ecdf36145d0673c50835c80f87b9325db8' 
  AND token = 'HXvsATkfhCyYnQVgqLm1qmdPZ3PuQYK0udg7AC+SSDU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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