SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '279d13c9704d92f6d265d304df7b7c5f3e99ae5dc6f616d823ce623012774508' 
  AND token = 'O21vuwOHDqxmk4aBPtV/etVYk5cJEM/IKz6e4iUGSjc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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