SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3769689a4fa786d6255d725730d9ab60d388eac3dd2f78b460bbf2339d53c6ed' 
  AND token = 'C47r0WvPdtMiVhWMV2NiBZHqHYK1F1HB+KZDcVWjzRc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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