SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cea07fae01244d2fbaa0df7fb9ca6067274a9a81e50d447ea865281d02776dc' 
  AND token = 'B/rEmkk2kTnHe7CWyzh0aDBbQSbydk6PzrvWKshonmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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