SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b54f4efd730e09ad4d4f120fb71e491bf052cc05c1772cd928a13ef663de6c3' 
  AND token = '8XhzuQwAueZvnGq8yBkt+SdHiN8UZbuZTHR9+gxij+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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