SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd471461dca1c515e30d95ce863c6f14b20532f51cd5c69501da20c177afb7f9b' 
  AND token = '545q9hWEEh1jz5kXqj4Vu44aDoebtxg8EwuZO4FrlvQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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