SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35c6527c131ff44a14ff0a4a8f27218041aee8d88a52d3b30930c0b7729f73eb' 
  AND token = '/4hRKwPJVHZHSHtcZ8+fumT4/vLinN9u3KqbodpM/lE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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