SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5c404a951f7e66fe075d8e8e1edc3280ed33d9d5f1e4dc14310a65b4373dd8d' 
  AND token = '/pedZu+VkNxA5yDtacyUUVvXshFVcz3XmrbBP9tLqHc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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