SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52e40b44afd0a8ee7ce78b80e9398e3da8859138c536c7b00ceb7798ef993113' 
  AND token = '+3wZeSQFC+XP/zQmqrDQWvQwhINbv26+x9yr2rfxufQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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