SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a4470adfedc76fcb0335d684bf26e0f3596cf1563bf82921b2dac8e824449f6' 
  AND token = 'XMaTbxynbrsnxyjmzfNEJy1/BrOGXbGbIey3eODaOmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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