SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca7c6160e78325cbffce232856ebdbacae1eb70e839f6b7413b030c3e2df3846' 
  AND token = '/AGqQ6kuTuujJr/NJoXcXBbUFZ/61w7oRUsGz/XQZEs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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