SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d4f715485e4a7de8802ce6de05637719e4a07e66d45ad8b9dcf9e81289270a3' 
  AND token = 'X6selSVLp0uaZTXgxHmWGKPoMDAiOaJ9UmI2FNapjo8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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