SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b299b9dae82529338fb86504b7e161c33d29a55723aa525d8018b962c3a16c87' 
  AND token = 'ZUK+YpdYdl35fyjJyVjK5bbQRp5tGo2VtbgZ7ERxU8Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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