SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2de0ef9a788958ad4a9c8e46cdc9c2d2fcc29deb7adda69400a2d079d301e513' 
  AND token = 'sPzrzxzouREFiKcKhW0JTEucVtutPbKw2K16Wfeo21o=' 
  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"
    }
  }
}