SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1611b1976f99066448806bb10f849da08eac9c0ab3670598faa195b620173e42' 
  AND token = '2QjjSViy4ilP2117UeFQe2OrVYQyGrs4CigbkMnupsY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}