SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '300bfaa01dff507fbac362cbfb79cdce4463849c6437fcb1903ec2adec727a78' 
  AND token = 'carWLZZ9tTKKZ7krnykHcHcOv7PrfCE5AgbHOoQlVh0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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