SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'f7371e461935a281c31a7aa38ada754728411558aef648d0a3f71f32b365509f' 
  AND token = '+0T+rPf0rsfhG1WIs9xnmoWWn6S8k1f+8NyZhv3vi1M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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