SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74350888d01389e72b310edcafbb1d1c0508de912ff80180632cd5dbc6c9ee83' 
  AND token = 'sVHgVKacW4rMr8BNYMQPblRa8I717rMU+DdOequzYEM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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