SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d45bbd6d42ab023200062c539e8e3955348200b272de1a3f31b81f2679be15f' 
  AND token = '0QFJAzhB1gjh6LMAK1SohPrfGwJE1oVUCz+SZpVD+wI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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