SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '928a1f4f6cca51ee06db653c73c6db63b4ccbec426ad2b47f0513292de243b86' 
  AND token = '7f8ZbUkGq/WVIYoHbZQoK2DtKVhNPVLG0zVTv2XAOx0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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