SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb0d170d16e150c24cee0dc8d4367ad5bed916496ea37eabdbfb319df2ec63ca' 
  AND token = 'UwKUBj+nKfTjyD+cVmL5cEwm5F33yyU0Gznt6Nrnz8M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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