SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3930ff5332e869c559efda09424072f163ce3d0084474eb5449a29607ef8af9e' 
  AND token = 'sXO4BwYh+v5NUvGIj9KCEJCOOwuX2orHsVJq9Owr47s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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