SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79c73388454a8f67dc3dbee68328f44d45d6cfa11279962a9b65b51371f54e78' 
  AND token = 'jTJT0Yw7xA6iY/kNn9tLj/A8cSaG8vWKdgzedZDxoFc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}